The present invention relates to a mechanical and electrical connection between an extruded metal profile and a cast metal member, with the cast member being provided with a peg-like projection which is adapted to the interior configuration of the extruded profile and can be inserted thereinto.
Such connections are customary, for example, in rectangular frontal frames for housings to accommodate plug-in modules or module carriers of electronic devices. It is necessary to electrically connect the frontal frame with the housing. This poses no difficulty in frontal frames that are cast in one piece. If, however, the frame is constructed of extruded profiles which are connected at both their ends by way of cast members having peg-like projections which are inserted into the extruded profile, the reliable mechanical and electrical connection of the individual components poses problems. Additional difficulties result from the fact that the connection must permit the subsequent application of lacquer and burn-in of the frame without adversely affecting its function. Moreover, for aesthetic reasons, the connecting members should be invisible.
It is known to connect the individual frame portions by means of inserted corner pieces which are then wedged together. However, this type of connection is possible only with the use of additional components and some deformation. If the wedging pressure is too weak and the component is subject to mechanical stresses, the frame portions will be seated only loosely. Then a secure electrical connection is no longer ensured.
Pressing the profile onto peg-like projection has the drawback that a satisfactory result can be realized only with the use of a hollow profile. Moreover, the exact adherence to close manufacturing tolerances is absolutely necessary.
It is also known to connect metal components together by gluing. Gluing requires great care and adherence to dimensions. The adhesive must be conductive and is therefore expensive. Since the burn-in temperature is limited by the adhesive, the selection of available lacquers is restricted.
It is possible to directly secure together by deformation an extruded profile with the projection of a cast member. However, under high mechanical stresses, the electrical contact may be destroyed.
Finally, it is possible to realize the required connection by screwing or welding the parts together. However, these types of connection also have their drawbacks. Screwing together involves complicated assembly and is disadvantageous for aesthetic reasons since the screw heads are difficult to accommodate invisibly. Welds are possibly only if the two materials are identical which is generally not the case if extruded profiles are to be connected with cast members.